Çharles N. Bernstein

The human endogenous intestinal microflora is an essential "organ" in providing nourishment, regulating epithelial development, and instructing innate immunity; yet, surprisingly, basic features remain poorly described. We examined 13,355 prokaryotic ribosomal RNA gene sequences from multiple colonic mucosal sites and feces of healthy subjects to improve our understanding of gut microbial diversity. A majority of the bacterial sequences corresponded to uncultivated species and novel microorganisms. We discovered significant intersubject variability and differences between stool and mucosa community composition. Characterization of this immensely diverse ecosystem is the first step in elucidating its role in health and disease.

The discovery of a series of genetic and serological markers associated with disease susceptibility and phenotype in inflammatory bowel disease has led to the prospect of an integrated classification system involving clinical, serological and genetic parameters. The Working Party has reviewed current clinical classification systems in Crohn's disease, ulcerative colitis and indeterminate colitis, and provided recommendations for clinical classification in practice. Progress with respect to integrating serological and genetic markers has been examined in detail, and the implications are discussed. While an integrated system is not proposed for clinical use at present, the introduction of a widely acceptable clinical subclassification is strongly advocated, which would allow detailed correlations among serotype, genotype and clinical phenotype to be examined and confirmed in independent cohorts of patients and, thereby, provide a vital foundation for future work.

BACKGROUND: Infliximab, a monoclonal antibody against tumor necrosis factor, is an effective maintenance therapy for patients with Crohn's disease without fistulas. It is not known whether infliximab is an effective maintenance therapy for patients with fistulas. METHODS: We performed a multicenter, double-blind, randomized, placebo-controlled trial to evaluate the efficacy of infliximab maintenance therapy in 306 adult patients with Crohn's disease and one or more draining abdominal or perianal fistulas of at least three months' duration. Patients received 5 mg of infliximab per kilogram of body weight intravenously on weeks 0, 2, and 6. A total of 195 patients who had a response at weeks 10 and 14 and 87 patients who had no response were then randomly assigned to receive placebo or 5 mg of infliximab per kilogram every eight weeks and to be followed to week 54. The primary analysis was the time to the loss of response among patients who had a response at week 14 and underwent randomization. RESULTS: The time to loss of response was significantly longer for patients who received infliximab maintenance therapy than for those who received placebo maintenance (more than 40 weeks vs. 14 weeks, P<0.001). At week 54, 19 percent of patients in the placebo maintenance group had a complete absence of draining fistulas, as compared with 36 percent of patients in the infliximab maintenance group (P=0.009). CONCLUSIONS: Patients with fistulizing Crohn's disease who have a response to induction therapy with infliximab have an increased likelihood of a sustained response over a 54-week period if infliximab treatment is continued every 8 weeks.

BACKGROUND: The objective of the current study was to determine the incidence of cancer among persons with inflammatory bowel disease (IBD) and to compare these incidence rates with those of the non-IBD population using population-based data from the administrative claims data of Manitoba's universal provincial insurance plan (Manitoba Health). METHODS: IBD patients were matched 1:10 to randomly selected members of the population without IBD based on year, age, gender, and postal area of residence. The incidence of cancer was determined by linking records from the IBD and non-IBD cohorts with the comprehensive Cancer Care Manitoba registry. Incidence rates and rate ratios (IRR) were calculated based on person-years of follow-up (Crohn's disease = 21,340 person-years and ulcerative colitis [UC] = 19,665 person-years) for 1984-1997. RESULTS: There was an increased IRR of colon carcinoma for both Crohn disease patients (2.64; 95% confidence interval [95% CI], 1.69-4.12) and UC patients (2.75; 95% CI, 1.91-3.97). There was an increased IRR of rectal carcinoma only among patients with UC (1.90; 95% CI, 1.05-3.43) and an increased IRR of carcinoma of the small intestine only in Crohn disease patients (17.4; 95% CI, 4.16-72.9). An increased IRR of extraintestinal tumors was observed only for the liver and biliary tract in both Crohn disease patients (5.22; 95% CI, 0.96-28.5) and UC patients (3.96; 95% CI, 1.05-14.9). There was an increased IRR of lymphoma for males with Crohn disease only (3.63; 95% CI, 1.53-8.62), and this finding did not appear to be related to use of immunomodulatory therapy. Compared with controls, Crohn's disease was associated with an increased risk of cancer overall, but UC was not. CONCLUSIONS: There appear to be similar increased risks for developing colon carcinoma and hepatobiliary carcinoma among patients with Crohn disease and UC. There is an increased risk of developing rectal carcinoma in UC patients, an increased risk of developing carcinoma of the small bowel in Crohn disease patients, and an increased risk of developing lymphoma among males with Crohn disease.